Update aws-go-sdk to support EKS Pod Identity

[bhvishal9]

Is your feature request related to a problem? Please describe.
Currently boundary doesn't support EKS pod identity which is a much simpler way to provide AWS access. The newer versions of aws-sdk-go support EKS pod identity, it was added in version 1.47.1.

There is an error if you use the latest version of boundary 0.18.0 on EKS

Error parsing KMS configuration: error setting configuration on the kms plugin: rpc error: code = Unknown desc = error fetching AWS KMS wrapping key information: NoCredentialProviders: no valid providers in chain. Deprecated.
For verbose messaging see aws.Config.CredentialsChainVerboseErrors

Describe the solution you'd like
Boundary should work on EKS if using EKS pod identity for providing KMS access.

Describe alternatives you've considered
The other solution is to use IAM roles for service accounts or pass access keys/secret access keys to the configuration.